1. Field of the Invention
The present invention relates to an axisymmetric and wide-vectoring turbojet-engine exhaust nozzle.
2. Related Art
More specifically the invention relates to an axisymmetric, wide-vectoring turbojet-engine exhaust nozzle comprising a converging-flaps drive arrangement supported on a vectoring structure which in turn is mounted on the downstream end of an exhaust housing having an axis X, said vectoring structure being able to tilt or rotate about a fixed center O located on the axis X. A means also is provided to tilt or rotate the vectoring structure and to regulate the exhaust cross-section of the converging flaps.
European Patent Document 0,029,773 discloses a converging nozzle of this kind wherein the vectoring structure is connected to the exhaust housing by elastic means reacting all transverse loads. The axial loads are reacted by linear control actuators tipping the vectoring structure. A second set of linear actuators anchored in the vectoring structure is used to regulate the nozzle exhaust cross-section.
European Patent Document 0,060,763 suggests a vectoring structure fitted with spherical bearings cooperating with spherical supports of the exhaust housing with insertion of a guide and roller system between the bearings and the support. The vectoring structure is prevented from rotation at least one guide assembly consisting of a slide affixed to the stationary structure and one roller affixed to the vectoring structure. Vectoring is implemented by a set of linear actuators anchored in the exhaust housing, and the nozzle cross-section is regulated by a second set of linear actuators borne on the vectoring structure. In this design the linear actuators implementing the directionality of the vectoring structure must react forces arising from friction with, and rolling on, the structural spheres which as a rule are large and consequently sensitive to thermal and mechanical expansions and warping.
In the two above cited documents, the converging flaps hinge on the downstream end of the vectoring structure which in turn bears the linear control actuators for the flaps, as a result of which the weight of the pivoting portion is increased and the response time to vector the nozzle is lengthened.
U.S. Pat. No. 4,984,741 relates to a wide-vectoring, converging-diverging nozzle wherein the converging flaps are mounted to slide axially on a spherical vectoring structure and are driven by linear actuators supported on said structure. The connection between the vectoring structure and the exhaust housing is implemented by two pairs of diametrically opposite radial stubs which are firmly affixed to axial bases on the vectoring structure and the exhaust housing and which slide in brackets in the corresponding bases of the other part. These stubs absorb the transverse loads, however the axial loads are absorbed by the linear control actuators tipping the vectoring structure.